This application claims the benefit of Korean Application No. 2002-1851, filed Jan. 12, 2002, in the Korean Patent Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a reception line break detection apparatus, which is insulated with ease and allows a reduced number of component parts and power sources.
2. Description of the Related Art
In general, data transmission apparatuses are used to transmit data from transmission sides to reception sides. A line drive for the transmission side and a line receiver for the reception side are employed in the data transmission apparatus. The line drive and the line receiver are connected to each other via transmission lines, each including two strands so as to receive and transmit data.
FIG. 1 is a diagram showing a conventional reception line break detection apparatus applied to a motor control system, where data is transmitted and received through three channels CH1, CH2, and CH3. Signals outputted through a line drive 1 in a transmission side are transmitted through transmission lines of the channels, and the signals are received by a line receiver 4 in a reception side through terminating circuits 3. Meanwhile, the reception side is equipped with a plurality of potentiometers 2 and an OR gate 5 so as to detect breaks of reception lines on the reception sides.
Each of the potentiometers 2 outputs an error signal FAULT indicating a break of a reception line when a potential difference of the reception line, that is, whether a voltage of the reception line (hereinafter, referred to as a xe2x80x9cline voltagexe2x80x9d), deviates from a standard voltage (prescribed by an international standards organization). The error signal is provided to each of the channels. When the OR gate 5 receives an error signal FAULT from any of the potentiometers 2, the OR gate 5 outputs a break detection signal to a receiver controller to notify the receiver controller of an occurrence of a line break on the reception side.
Referring to FIG. 2, the potentiometer 2 is provided for each of the reception lines connected to the channels CH1, CH2, and CH3 extending from the line drive 1, connected to two lead-in wires branched off from each of the reception lines, including a plurality of resistors R1 to R8, three comparators C1 to C3 and an OR gate, and three kinds of power sources VCC, VEE, and GND.
The comparator C1 differentially amplifies the lead-in voltages IN+ and INxe2x88x92, and outputs the amplified voltages to a positive terminal of the comparator C2 and a negative terminal of the comparator C3. The comparator C2 compares the amplified voltage with a reference voltage xe2x88x920.6 V inputted to a negative terminal of the comparator C2, and outputs a detection signal if this amplified voltage is lower than this reference voltage. The comparator C3 compares the amplified voltage with a reference voltage +0.6 V inputted to a positive terminal of the comparator C3, and outputs the detection signal if this amplified voltage is lower than this reference voltage. As a result, the OR gate outputs the error signal FAULT to the receiver controller when the detection signal is inputted to the OR gate from any of the two comparators C2 and C3. The signals differentially amplified in the comparator C1 are compared with reference voltages by two comparators C2 and C3 so as to detect line breaks for all the signals inputted normally or in reverse because the lead-in wire voltages IN+ and INxe2x88x92 can be applied normally or in reverse.
In the conventional reception line break detection apparatus, a potential difference and a reference voltage 0.6 V must be precisely compared with each other so as to ensure reliability of the detection operation of the apparatus. To this end, a plurality of component parts such as resistors and comparators are employed, so the manufacturing costs of the conventional reception line break detection apparatus are high. Additionally, three different types of power sources are used, so it is difficult to insulate the apparatus.
Accordingly, the present invention has been made keeping in mind the above problems occurring in the conventional art, and an object of the present invention is to provide a reception line break detection apparatus including a relatively small number of component parts, which can be easily insulated due to a reduction in a number of power sources.
In order to accomplish the above and other objects, the present invention provides a reception line break detection apparatus, including: a transmission-side line drive; a reception line; a switching element; a reception-side line receiver receiving signals transmitted from the transmission-side line drive through the reception line; and a break detection unit detecting a break of the reception line using the switching element, wherein the switching element is switched according to a line voltage of lead-in wires branched off from the reception line.
To achieve the above and other objects, the present invention provides a reception line break detection apparatus transmitting and receiving data, including: a transmission-side line drive transmitting signals; a reception-side line receiver receiving the signals; a reception line electrically coupling the transmission-side line drive to the reception-side line receiver; and a break detection unit including an input side connected to the reception line and an output side insulated from the reception line, wherein the break detection unit detects a line break of the reception line when a line voltage of the reception line is lower than a reference voltage and outputs an error signal indicative thereof.
These together with other objects and advantages, which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.